20240414 Finished

Cargo.toml

@@ -9,7 +9,7 @@ reqwest = { version = "0.11.22", features = ["json"] }
 serde = "1.0"
 serde_json = "1.0"
 serde_derive = "1.0"
-rand = "0.6.5"
+rand = "0.8.5"
 regex = "1.3.4"
 futures = { version = "0.3.11", features = ["thread-pool"] }
 surf = "1.0.3"

src/problem/mod.rs

@@ -101,4 +101,5 @@ mod p121_best_time_to_buy_and_sell_stock;
 mod p122_best_time_to_buy_and_sell_stock_ii;
 mod p55_jump_game;
 mod p45_jump_game_ii;
-mod p274_h_index;
+mod p274_h_index;
+mod p380_insert_delete_getrandom_o1;

src/problem/p380_insert_delete_getrandom_o1.rs

@@ -0,0 +1,90 @@
+/**
+ * [380] Insert Delete GetRandom O(1)
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+use rand::{rngs::ThreadRng, Rng};
+use std::collections::HashMap;
+
+struct RandomizedSet {
+    array: Vec<i32>,
+    pos_table: HashMap<i32, usize>,
+    pos_now: usize,
+    rng: ThreadRng
+}
+
+
+/**
+ * `&self` means the method takes an immutable reference.
+ * If you need a mutable reference, change it to `&mut self` instead.
+ */
+impl RandomizedSet {
+
+    fn new() -> Self {
+        RandomizedSet {
+            array: vec![0;200_001],
+            pos_table: HashMap::new(),
+            pos_now: 0,
+            rng: rand::thread_rng()
+        }
+    }
+    
+    fn insert(&mut self, val: i32) -> bool {
+        if self.pos_table.contains_key(&val) {
+            return false;
+        }
+
+        self.array[self.pos_now] = val;
+        self.pos_table.insert(val, self.pos_now);
+        self.pos_now += 1;
+        true
+    }
+    
+    fn remove(&mut self, val: i32) -> bool {
+        return match self.pos_table.get(&val) {
+            Some(&pos) => {
+                let last = self.array[self.pos_now - 1];
+                self.pos_table.insert(last, pos);
+                self.array[pos] = last;
+                self.pos_now -= 1; 
+                self.pos_table.remove(&val);
+
+                true
+            },
+            None => false
+        }
+    }
+    
+    fn get_random(&mut self) -> i32 {
+        let pos = self.rng.gen_range(0..self.pos_now);
+        self.array[pos]
+    }
+}
+
+/**
+ * Your RandomizedSet object will be instantiated and called as such:
+ * let obj = RandomizedSet::new();
+ * let ret_1: bool = obj.insert(val);
+ * let ret_2: bool = obj.remove(val);
+ * let ret_3: i32 = obj.get_random();
+ */
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_380() {
+        let mut set = RandomizedSet::new();
+        assert!(set.insert(0));
+        assert!(set.insert(1));
+        assert!(set.remove(0));
+        assert!(set.insert(2));
+        assert!(set.remove(1));
+        assert_eq!(2, set.get_random());
+    }
+}